How long do you run your crank?

Blackjack31
Profile picture for user Blackjack31
Posts
403
Joined
5/21/2017
Location
Shelby, NC US
Blackjack31
Have a yz250 with about 100 hours on the crank. How long do y’all run your cranks? I thought about rebuilding mine before this next season (woods racing) but I think I’m gonna go another season on it. Opinions?
|
kb228
Profile picture for user kb228
Posts
6161
Joined
1/31/2018
Location
Mansfield, OH US
kb228 10/26/2019 12:18pm
10/26/2019 12:18pm
Rebuild it
CarlinoJoeVideo
Profile picture for user CarlinoJoeVideo
Posts
7358
Joined
11/30/2013
Location
Portland/Los Angeles, CA US
Fantasy
2361st
CarlinoJoeVideo 10/26/2019 3:49pm
10/26/2019 3:49pm
Did you do a piston at 100?

I’d change the piston and check the vertical play. Depends on the riding and how you cared for the bike. You could get 150 out of it.
4
DynoDan22
Profile picture for user DynoDan22
Posts
775
Joined
9/7/2011
Location
Victorville, CA US
DynoDan22 10/26/2019 4:33pm
10/26/2019 4:33pm Edited Date/Time 10/26/2019 4:33pm
It's all relative to maintenance and how you ride obviously, but as a rule of thumb, with a good maintenance schedule 250 2-strokes usually can go 100-150hrs on cranks. After that, you're on borrowed time. Top ends on 250 2T's can go 40-70hrs. When in doubt, just rebuild it. I always prefer OEM replacement parts but that's just me. At 100hrs, I'd just rebuild the crank and be done with it.
2
rob162
Profile picture for user rob162
Posts
609
Joined
7/8/2015
Location
IL US
rob162 10/26/2019 6:22pm
10/26/2019 6:22pm
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs out of it anything after that your asking to spend thousands to save 200-300 dollars. Get it rebuilt. New main bearings and enjoy for another 80 hrs
2

The Shop

See All »
JMCR250
Profile picture for user JMCR250
Posts
274
Joined
8/26/2018
Location
Chesterfield, MO US
JMCR250 10/27/2019 8:54am
10/27/2019 8:54am Edited Date/Time 10/27/2019 8:54am
Just replaced my 05 CR250 crank at about 150-200 hours. Probably went too long, but all's well that ends well. I do notice it has less vibration since the crank replacement.
Blackjack31
Profile picture for user Blackjack31
Posts
403
Joined
5/21/2017
Location
Shelby, NC US
Blackjack31 10/27/2019 10:00am
10/27/2019 10:00am
May just rebuild it. I had 115 hours on a yz125 top end and the crank was still good haha. I guess they don’t make the parts as good or something now days. Everybody puts like 100 hours on a crank. I know so many people who will have 300 hours on a crank. And they are fast people. Probably be better just to rebuild it and be safe.
Blackjack31
Profile picture for user Blackjack31
Posts
403
Joined
5/21/2017
Location
Shelby, NC US
Blackjack31 10/27/2019 10:02am
10/27/2019 10:02am
rob162 wrote:
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs...
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs out of it anything after that your asking to spend thousands to save 200-300 dollars. Get it rebuilt. New main bearings and enjoy for another 80 hrs
Thousands?! Geez you have an expensive 2 stroke
rob162
Profile picture for user rob162
Posts
609
Joined
7/8/2015
Location
IL US
rob162 10/28/2019 8:46am
10/28/2019 8:46am
rob162 wrote:
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs...
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs out of it anything after that your asking to spend thousands to save 200-300 dollars. Get it rebuilt. New main bearings and enjoy for another 80 hrs
Blackjack31 wrote:
Thousands?! Geez you have an expensive 2 stroke
Ive seen cranks go bad more often then not go bad and take the whole motor out with it. The entire motor everything had to be replaced nothing could be rebuilt somtimes including the crank. So cases, head, crank clutch,power valve reeds and somtimes even the pipe.
If youre lucky just need to rebuild the crank, a jug and rebuild the head which is still about a grand in parts and rebuilding parts not including labor to put the motor back together. Like i said can you get more the 80 hrs but why chance blowing the entire motor and having to start from scratch. My motto is once you hit 80 on 2 strokes the next off season it should be rebuilt. On 4 strokes 100 hrs. Plain bearing motors can go longer yes depending on rider but again why wait to long and have to build a whole motor from scratch.
1
kb228
Profile picture for user kb228
Posts
6161
Joined
1/31/2018
Location
Mansfield, OH US
kb228 10/28/2019 9:45am
10/28/2019 9:45am
rob162 wrote:
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs...
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs out of it anything after that your asking to spend thousands to save 200-300 dollars. Get it rebuilt. New main bearings and enjoy for another 80 hrs
Blackjack31 wrote:
Thousands?! Geez you have an expensive 2 stroke
Cylinder replate - $300
Set of cases - $4/500
New crank -$250
Piston kit - $150
Bearings - $300+
Gaskets & seals - $150??

Stuff adds up fast and i didnt even mention anything on the clutch side or tranny or if youre doing it yourself or not.
1
Blackjack31
Profile picture for user Blackjack31
Posts
403
Joined
5/21/2017
Location
Shelby, NC US
Blackjack31 10/28/2019 1:35pm
10/28/2019 1:35pm
kb228 wrote:
Cylinder replate - $300 Set of cases - $4/500 New crank -$250 Piston kit - $150 Bearings - $300+ Gaskets & seals - $150?? Stuff adds...
Cylinder replate - $300
Set of cases - $4/500
New crank -$250
Piston kit - $150
Bearings - $300+
Gaskets & seals - $150??

Stuff adds up fast and i didnt even mention anything on the clutch side or tranny or if youre doing it yourself or not.
If I’m unlucky enough that it ruins my cases and $300 worth of bearings then I’m retiring
kb228
Profile picture for user kb228
Posts
6161
Joined
1/31/2018
Location
Mansfield, OH US
kb228 10/28/2019 2:07pm
10/28/2019 2:07pm Edited Date/Time 10/28/2019 2:08pm
It costs $190 to rebuild a crank.. i dont understand why you wouldnt do that especially if youre already tearing it down.
1
Paul_Pitzonka
Profile picture for user Paul_Pitzonka
Posts
694
Joined
5/1/2018
Location
Grand Terrace, CA US
Paul_Pitzonka 10/28/2019 2:59pm
10/28/2019 2:59pm
kb228 wrote:
Cylinder replate - $300 Set of cases - $4/500 New crank -$250 Piston kit - $150 Bearings - $300+ Gaskets & seals - $150?? Stuff adds...
Cylinder replate - $300
Set of cases - $4/500
New crank -$250
Piston kit - $150
Bearings - $300+
Gaskets & seals - $150??

Stuff adds up fast and i didnt even mention anything on the clutch side or tranny or if youre doing it yourself or not.
Blackjack31 wrote:
If I’m unlucky enough that it ruins my cases and $300 worth of bearings then I’m retiring
Then be prepared to retire... I’ve seen way too many destroyed cases from bad cranks, transmissions breaking, worn out bearings, etc... it’s the nature of the sport, I’d rather use a shorter service intervals than take a chance and push it longer... there’s a reason it’s called preventative maintenance. Rebuild the crank it’s cheap reassurance and peace of mind...
rob162
Profile picture for user rob162
Posts
609
Joined
7/8/2015
Location
IL US
rob162 10/28/2019 4:30pm
10/28/2019 4:30pm
kb228 wrote:
Cylinder replate - $300 Set of cases - $4/500 New crank -$250 Piston kit - $150 Bearings - $300+ Gaskets & seals - $150?? Stuff adds...
Cylinder replate - $300
Set of cases - $4/500
New crank -$250
Piston kit - $150
Bearings - $300+
Gaskets & seals - $150??

Stuff adds up fast and i didnt even mention anything on the clutch side or tranny or if youre doing it yourself or not.
Blackjack31 wrote:
If I’m unlucky enough that it ruins my cases and $300 worth of bearings then I’m retiring
Paul_Pitzonka wrote:
Then be prepared to retire... I’ve seen way too many destroyed cases from bad cranks, transmissions breaking, worn out bearings, etc... it’s the nature of the...
Then be prepared to retire... I’ve seen way too many destroyed cases from bad cranks, transmissions breaking, worn out bearings, etc... it’s the nature of the sport, I’d rather use a shorter service intervals than take a chance and push it longer... there’s a reason it’s called preventative maintenance. Rebuild the crank it’s cheap reassurance and peace of mind...
Not to mention you lock up a motor 1 time in on the face of a big jump or in mid air. That crank rebuild 150 plus rod and bearings is a lot cheaper then the hospital bill! Lot less scary to.
1
seth505
Profile picture for user seth505
Posts
9376
Joined
4/1/2008
Location
SD, CA US
Fantasy
1271st
seth505 10/29/2019 2:55pm
10/29/2019 2:55pm
rob162 wrote:
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs...
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs out of it anything after that your asking to spend thousands to save 200-300 dollars. Get it rebuilt. New main bearings and enjoy for another 80 hrs
Blackjack31 wrote:
Thousands?! Geez you have an expensive 2 stroke
rob162 wrote:
Ive seen cranks go bad more often then not go bad and take the whole motor out with it. The entire motor everything had to be...
Ive seen cranks go bad more often then not go bad and take the whole motor out with it. The entire motor everything had to be replaced nothing could be rebuilt somtimes including the crank. So cases, head, crank clutch,power valve reeds and somtimes even the pipe.
If youre lucky just need to rebuild the crank, a jug and rebuild the head which is still about a grand in parts and rebuilding parts not including labor to put the motor back together. Like i said can you get more the 80 hrs but why chance blowing the entire motor and having to start from scratch. My motto is once you hit 80 on 2 strokes the next off season it should be rebuilt. On 4 strokes 100 hrs. Plain bearing motors can go longer yes depending on rider but again why wait to long and have to build a whole motor from scratch.
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took out the cases or anything else for that matter.
erik_94COBRA
Profile picture for user erik_94COBRA
Posts
951
Joined
7/21/2016
Location
Houston-ish, TX US
erik_94COBRA 10/29/2019 3:50pm
10/29/2019 3:50pm
seth505 wrote:
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took...
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took out the cases or anything else for that matter.
Had both happen: Seized crank on '01 CR250 that didn't hurt anything (pre-mix problem) and seized crank on '03 CR250 that ruined cylinder, cases, and crank (stuck WOT on cold start).

150 hrs doesn't seem too extreme for woods/offroad.
1
GoggleFiend904 10/29/2019 7:44pm
10/29/2019 7:44pm
rob162 wrote:
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs...
You can get more than 100 hrs with a properly built crank. Key word CAN. As someone who rebuilds cranks every day if you get 80hrs out of it anything after that your asking to spend thousands to save 200-300 dollars. Get it rebuilt. New main bearings and enjoy for another 80 hrs
Blackjack31 wrote:
Thousands?! Geez you have an expensive 2 stroke
rob162 wrote:
Ive seen cranks go bad more often then not go bad and take the whole motor out with it. The entire motor everything had to be...
Ive seen cranks go bad more often then not go bad and take the whole motor out with it. The entire motor everything had to be replaced nothing could be rebuilt somtimes including the crank. So cases, head, crank clutch,power valve reeds and somtimes even the pipe.
If youre lucky just need to rebuild the crank, a jug and rebuild the head which is still about a grand in parts and rebuilding parts not including labor to put the motor back together. Like i said can you get more the 80 hrs but why chance blowing the entire motor and having to start from scratch. My motto is once you hit 80 on 2 strokes the next off season it should be rebuilt. On 4 strokes 100 hrs. Plain bearing motors can go longer yes depending on rider but again why wait to long and have to build a whole motor from scratch.
A good friend of mine smoked the crank on his yz250. I believe he paid $1400 to fix all the damage, about an hour later he snapped another crank/rod and the damage was even worse than the first time. Oem cylinder alone ran him 5-600 with a discount. I believe his cases got damaged this time around.

I’m at around 260-270 hours on a stock crank. I’ve heard the ktm cranks can last a long time, but now I’m thinking about replacing it when the top end is due. I’ll check for up and down play as I usually do and make my decision
Blackjack31
Profile picture for user Blackjack31
Posts
403
Joined
5/21/2017
Location
Shelby, NC US
Blackjack31 10/30/2019 7:28am
10/30/2019 7:28am
seth505 wrote:
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took...
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took out the cases or anything else for that matter.
Yeah I’ve never sized a crank (knock on a lot of wood) but the people I know who have, haven’t replaced cases. I’m sitting at around 100 hours on the crank. I’m gonna do my top end and check for play and rotate the needle bearings and see if I can see any heat marks or stress on it. Then make my decision. I have an extra crank and cylinder sitting in the building. Just gonna go check it real good
YZed250
Profile picture for user YZed250
Posts
1055
Joined
11/9/2014
Location
Costa Mesa, CA US
YZed250 10/31/2019 2:26pm
10/31/2019 2:26pm Edited Date/Time 10/31/2019 2:32pm
seth505 wrote:
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took...
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took out the cases or anything else for that matter.
Blackjack31 wrote:
Yeah I’ve never sized a crank (knock on a lot of wood) but the people I know who have, haven’t replaced cases. I’m sitting at around...
Yeah I’ve never sized a crank (knock on a lot of wood) but the people I know who have, haven’t replaced cases. I’m sitting at around 100 hours on the crank. I’m gonna do my top end and check for play and rotate the needle bearings and see if I can see any heat marks or stress on it. Then make my decision. I have an extra crank and cylinder sitting in the building. Just gonna go check it real good
I replaced my YZ250 crank w a hotrods kit at 100 hours and it was never the same. too many vibes after that.

Out west, we run our bikes out to the limiter and wide open when we run in the dessert so the crank runs with minimal lube. Everything depends on jetting and setup (advance, compression) to keep it together. Motor won't run 50 hours under those conditions with the wrong setup.

However, where I used to ride/race in the south east of Australia, I would ride a lot of woods and be struggling for traction on technical trails, much of the time. 2-stroke motors last a lot longer under those conditions so long as the intake is clean and they don't get too hot.

Now that I'm on my KTM 250SX, I'm definitely running it to 100 hours before I lift the cylinder. That's just because I'm older/slower and the build quality is pretty unbelievable and I feel confident in the motor setup.

If I dust or overheat the motor, then that changes everything. If I start to hear growling or feel vibes (crank) then, that also changes things and I'll think about a rebuild.

Pit Row

See All »
rob162
Profile picture for user rob162
Posts
609
Joined
7/8/2015
Location
IL US
rob162 10/31/2019 2:54pm
10/31/2019 2:54pm Edited Date/Time 10/31/2019 8:34pm
seth505 wrote:
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took...
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took out the cases or anything else for that matter.
Blackjack31 wrote:
Yeah I’ve never sized a crank (knock on a lot of wood) but the people I know who have, haven’t replaced cases. I’m sitting at around...
Yeah I’ve never sized a crank (knock on a lot of wood) but the people I know who have, haven’t replaced cases. I’m sitting at around 100 hours on the crank. I’m gonna do my top end and check for play and rotate the needle bearings and see if I can see any heat marks or stress on it. Then make my decision. I have an extra crank and cylinder sitting in the building. Just gonna go check it real good
YZed250 wrote:
I replaced my YZ250 crank w a hotrods kit at 100 hours and it was never the same. too many vibes after that. Out west, we...
I replaced my YZ250 crank w a hotrods kit at 100 hours and it was never the same. too many vibes after that.

Out west, we run our bikes out to the limiter and wide open when we run in the dessert so the crank runs with minimal lube. Everything depends on jetting and setup (advance, compression) to keep it together. Motor won't run 50 hours under those conditions with the wrong setup.

However, where I used to ride/race in the south east of Australia, I would ride a lot of woods and be struggling for traction on technical trails, much of the time. 2-stroke motors last a lot longer under those conditions so long as the intake is clean and they don't get too hot.

Now that I'm on my KTM 250SX, I'm definitely running it to 100 hours before I lift the cylinder. That's just because I'm older/slower and the build quality is pretty unbelievable and I feel confident in the motor setup.

If I dust or overheat the motor, then that changes everything. If I start to hear growling or feel vibes (crank) then, that also changes things and I'll think about a rebuild.
Not saying this is your issue but the most common reason for vibes on a hot rods crank that I've found from guys running them is they buy them and just throw them in. Hot rods, weisco and pro-x cranks always alway alway have to be trued up again whem ypu buy them. It's some what common for one out the box be perfectly in spec. Yet some you find were at the limit or just out. It's a shipping issue. Those boxes get tossed around so much from the time they box it ship it to distributors, sometime ship it again to another warehouse then to dealer then ship it to you. I know they are packed very well but it happens.

Im not a fan of hot rods main bearings, use oem or a bearing house. Roller bearing set ups work the best.

Wiesco had some problems with their cranks and clutch baskets years ago but that's well in the past.

Also if your looking for the best rod money can buy call crank works they have a in-house built rod that is ridiculously good. You'll have to change the big end bearings before the rod.
1
YZed250
Profile picture for user YZed250
Posts
1055
Joined
11/9/2014
Location
Costa Mesa, CA US
YZed250 10/31/2019 2:56pm
10/31/2019 2:56pm
seth505 wrote:
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took...
More often than not you've seen the crank take out the entire motor? I've seized a few cranks in my day and none of them took out the cases or anything else for that matter.
Blackjack31 wrote:
Yeah I’ve never sized a crank (knock on a lot of wood) but the people I know who have, haven’t replaced cases. I’m sitting at around...
Yeah I’ve never sized a crank (knock on a lot of wood) but the people I know who have, haven’t replaced cases. I’m sitting at around 100 hours on the crank. I’m gonna do my top end and check for play and rotate the needle bearings and see if I can see any heat marks or stress on it. Then make my decision. I have an extra crank and cylinder sitting in the building. Just gonna go check it real good
I like this approach: look, listen feel for play and keep running it if it checks out.

Post a reply to: How long do you run your crank?